To determine the cost of goods sold (COGS) for the sale on May 20 using the FIFO (First In, First Out) inventory cost method, we need to follow these steps:
1. Track the inventory changes: Record all purchases and sales chronologically and maintain the balance of inventory as per FIFO.
2. Compute the cost of the inventory used in May 20 sale: Start from the earliest inventory and use it until the required units for the sale are fulfilled.
### STEP 1: Track Inventory Changes
1. May 3: Purchase 9 units at \[tex]$15 each
\[
\text{Inventory:} 9 \text{ units at } \$[/tex]15 \text{ each}
\]
2. May 10: Sale of 5 units
[tex]\[
\text{Using FIFO, the 5 units sold are from the May 3 purchase.}
\][/tex]
[tex]\[
\text{Remaining Inventory:} (9 - 5) = 4 \text{ units at } \$15 \text{ each}
\][/tex]
3. May 17: Purchase 16 units at \[tex]$17 each
\[
\text{Inventory after purchase:} 4 \text{ units at } \$[/tex]15 \text{ each} \text{ and } 16 \text{ units at } \[tex]$17 \text{ each}
\]
4. May 20: Sale of 5 units
### STEP 2: Compute Cost of Inventory Used for May 20 Sale
Using FIFO, we start with the earliest inventory:
- First, use the 4 units from the May 3 purchase:
\[
4 \text{ units at } \$[/tex]15 = \[tex]$60
\]
- Then, use 1 unit from the May 17 purchase to make up the total of 5 units:
\[
1 \text{ unit at } \$[/tex]17 = \[tex]$17
\]
- Total Cost of Goods Sold (COGS) for May 20 sale:
\[
\$[/tex]60 + \[tex]$17 = \$[/tex]77
\]
### Conclusion:
The cost of goods sold for the sale on May 20 using the FIFO inventory cost method is:
[tex]\[
\boxed{77}
\][/tex]
Thus, the correct answer is:
d. \$77
